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Restriction Endonucleases >
Restriction Endonucleases >
XbaI |
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 Recognition Site:


 isoschizomers | compatible ends | single letter code
Source: A E. coli strain that carries the XbaI gene from Xanthomonas badrii (ATCC 11672).
Reagents Supplied: NEBuffer 4 (10X)
BSA (100X)
Enzyme Properties

 Activity in NEBuffers:
| NEBuffer 1: |  | 0% | | NEBuffer 2: |  | 100% | | NEBuffer 3: |  | 75% | | NEBuffer 4: |  | 100% |
When using a buffer other than the optimal (supplied) NEBuffer, it may be necessary to add more enzyme to achieve complete digestion.
Methylation Sensitivity:
| dam methylation: Blocked by overlapping | | dcm methylation: Not sensitive | | CpG methylation: Not sensitive |
Heat Inactivation: 65°C for 20 minutes
Survival in a Reaction: Minimum units to digest 1 µg of substrate DNA in 16 hours: 0.13 unit(s)
Reaction & Storage Conditions

 Reaction Conditions: 1X NEBuffer 4 Supplemented with 100 μg/ml Bovine Serum Albumin Incubate at
37°C.
1X NEBuffer 4: 20 mM Tris-acetate 50 mM potassium acetate 10 mM Magnesium Acetate 1 mM Dithiothreitol
pH 7.9 @ 25°C
Unit Definition: One unit is defined as the amount of enzyme required to digest 1 µg of λ DNA (dam-/HindIII digest) in 1 hour at 37°C in a total reaction volume of 50 µl.
Concentration: 20,000 units/ml and 100,000 units/ml
Unit Assay Substrate: λ DNA (dam-/Hind III digest)
Storage Conditions: 10 mM Tris-HCl 50 mM NaCl 1 mM Dithiothreitol 0.1 mM EDTA 200 µg/ml BSA 50% Glycerol
pH 7.4 @ 25°C
Storage Temperature: -20°C
Diluent Compatibility: Diluent A
FAQs


- Is XbaI affected by methylation?
- The NEB catalog has historically stated that activity in NEBuffer4 is less than 100% yet this enzyme is now supplied with NEBuffer4. What have you changed?
- Has the conversion to NEBuffer4 altered any of the properties of the restriction enzyme?
- If I have an old tube of enzyme, what NEBuffer should I use?
- Will the new enzyme work in the originally supplied NEBuffer?
- Why is NEB switching this restriction enzyme to NEBuffer 4?
Quality Control for Current Lot

 Quality control values for a specific lot can be found on the datacard which accompanies each product.
Ligation and Re-cutting:
After a 20-fold overdigestion with XbaI, > 95%
of the DNA fragments can be ligated with T4 DNA Ligase (at a 5' termini concentration of 1-2 μM)
at 16ºC. Of these ligated fragments, > 95% can be recut with XbaI.
16-Hour Incubation:
A 50 μl reaction containing 1 μg of DNA
and 200 units of XbaI incubated for 16 hours at 37ºC
resulted in a DNA pattern free of detectable nuclease degradation as determined by agarose gel electrophoresis.
Exonuclease Activity:
Incubation of a 50 μl reaction containing 200 units of XbaI with 1 μg of a mixture of single and double-stranded
[3H] E. coli DNA (205 cpm/μg) for 4 hours at 37ºC
released < 0.19% of the total radioactivity.
Endonuclease Activity:
Incubation of a 50 μl reaction containing 200 units of XbaI with 1 μg of
ΦX174 RF I DNA for 4 hours at 37ºC resulted
in < 10% conversion to RFII as determined by agarose gel electrophoresis.
Blue/White Screening Assay:
An appropriate vector is digested at a unique site within the
lacZα gene with a 10-fold excess of enzyme.
The vector DNA is then ligated, transformed, and plated onto Xgal/IPTG/Amp plates.
Successful expression of β-galactosidase is a function of how intact its gene remains after cloning,
an intact gene gives rise to a blue colony, removal of even a single base gives rise to a white colony.
Enzyme preparations must produce fewer than 3% white colonies to be Blue/White certified.
Reagents Sold Separately

 NEBuffer 4 BSA
Companion Products

 dam-/dcm- Competent E. coli
Legal

 Patents: New England Biolabs, Inc.: U.S. Patent No. 4,983,542
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